package LuoGu.集合求和;

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner s = new Scanner(System.in);
        List<Integer> list = new ArrayList<>();
        String temp = s.nextLine();
        Scanner ss = new Scanner(temp);
        while(ss.hasNext()){
            list.add(ss.nextInt());
        }
        int n = list.size();
        long ans = 1;
        long all = 0;
        for(int i=1;i<n;i++){
            ans *= 2;
        }
        for(int i=0;i<n;i++){
            all+=list.get(i);
        }
        System.out.print(ans*all);
    }
}

